FIAMME IN BOULDER AT TRAFALGAR FALLS

The Roseau ignimbrite represents pyroclastic deposits that were emplaced nearly 30,000 years ago in a violent eruption. At Trafalgar Falls we were able to see the welded nature of the unit in the flattened lense-shaped pumice fragments fiamme. These are evidence that a large thickness of material was deposited hot, such that the pumice fragments were plastically deformed. In this area the ignimbrite is over a hundred meters thick, whereas approximately 10 km away, closer to the coast it is only a few meters thick.